Ceresit ZU - Universal adhesive for polystyrene and mesh - 25kg
What is Ceresit ZU?
Ceresit ZU is a cement-based, highly flexible Universal Adhesive and Basecoat Mortar designed specifically for External Wall Insulation (EWI) systems using expanded (EPS) or extruded (XPS) polystyrene boards. It is a dual-purpose, fibre-reinforced product used both for fixing the insulation boards to the wall and creating the reinforced layer with mesh before applying the final render finish.
| Specification | Details |
|---|---|
| Material Base | Cement-based with mineral fillers and modifiers |
| Primary Use | Fixing and Basecoating EPS & XPS insulation boards |
| Consumption (Fixing) | Approx. 5.0 kg/m² |
| Consumption (Basecoat) | Approx. 4.0 kg/m² |
| Adhesion Strength | >0.1 MPa (breaking in EPS layer) |
| Application Temp | +5°C to +25°C |
| Key Features | Weather-resistant, durable, flexible, machine applicable |
- When should I use Ceresit ZU?
Use Ceresit ZU specifically for polystyrene (EPS or XPS) boards. Ceresit CT 190 is the dedicated, fibre-reinforced adhesive and basecoat for mineral wool (rockwool) insulation systems due to their different material properties and breathability requirements. - Does Ceresit ZU require a fiberglass mesh?
Yes. When used as a reinforced layer (basecoat), an alkali-resistant fiberglass mesh must be embedded into the wet mortar to provide crack resistance and structural integrity. - What substrates can Ceresit ZU be applied to?
Ceresit ZU shows good adhesion to sound and carrying substrates, such as concrete, masonry, plaster, and existing renders that are free from grease, dust, or bitumen. The adhesion of existing coatings should be checked before application.
- Mixing: Pour one 25kg bag into 4.5–5.0 litres of cool, clean water and mix until a homogenous, lump-free mass is obtained.
- Fixing Boards: Apply mortar in a "strip-and-dot" method (a band around the edge and several blobs in the center) and press the board firmly to the wall.
- Basecoat Application: After 24 hours (once dry), apply a layer of ZU with a notched trowel (10mm-12mm teeth).
- Mesh Embedding: Press the fiberglass mesh into the fresh mortar until it is no longer visible, then apply a final thin layer of ZU to smooth it out.
- Pro-Tip on Coverage: For the reinforced basecoat layer, aim for approximately 4.0 kg/m² consumption. This ensures sufficient coverage and strength without excessive thickness.
- Pro-Tip on Substrates: If applying to highly absorbent substrates like aerated concrete blocks, prime the surface first with Ceresit CT 17 Deep Penetrating Primer to ensure an even set and optimal adhesion.
CERESIT® ZU mortar is used to insulate the external walls of buildings using polystyrene boards. It is a component of complex external wall insulation systems (ETICS) of CERESIT Ceretherm buildings. CERESIT ZU mortar is used both for fixing EPS and XPS polystyrene boards, as well as for making a reinforced protective layer when insulating newly erected buildings and undergoing thermal renovation. Available pack size: 25 kg